Manchester United surrendered a two-goal lead and were fortunate not to be eliminated by a spirited Chelsea in the FA Cup quarter-final.

Javier Hernández and a Wayne Rooney free-kick made it 2-0 at the pause but a superb curling effort from the influential Eden Hazard and Ramires's equaliser earned Chelsea a replay.

It ended a disheartening week for Sir Alex Ferguson's side, who had David de Gea to thank for keeping them in the cup as the Spaniard made a brilliant late save from Juan Mata.

The chinks in United's armour were evident in the first 45 as they ceded possession regularly but Chelsea failed to capitalise, with Victor Moses wasteful and Frank Lampard squandering a routine opportunity.

Hernández had earlier scored his seventh goal past the Blues when Michael Carrick's visionary pass enabled him to lob Petr Čech for the opener.

Ramires celebrates his equaliser

Rooney ended an ambivalent week with a goal direct from a free-kick as his inswinger evaded everyone in the box to double the advantage inside 11 minutes.

Fifty-one minutes into the match, interim Chelsea coach Rafael Benítez withdrew Lampard and Moses for Hazard and John Obi Mikel to cries of "You don't know what you're doing" from the away supporters. Informed again he was "not welcome" and told to "f**k off" regularly, Benítez proved he did know what he was doing.

Hazard complemented the attacking triumvirate with Mata and Oscar as United panicked. The Belgian's goal before the hour mark prompted Ferguson to bring on Robin van Persie for Hernández when the execrable Tom Cleverley was flagging and offering his defence poor protection.

Chelsea made hay and deservedly equalised when a counter-attack led to Oscar assisting Ramires, who cut inside Jonny Evans and placed the ball into the corner of the net, via De Gea's fingertips.

United failed to respond as Chelsea's confidence grew and Čech became a mere spectator. Had Mata converted his presentable chance to win the match, Ferguson could have had no complaints. Even after that the Spaniard denied Hazard and Ashley Cole was too slow to react to capitalise on the rebound.

Benítez complimented De Gea for his late save although chose not to shake hands with his old adversary. Ferguson said on Friday it wasn't his style to "kick a man while he was down". This time it was Benítez who did the kicking.